## Trigonometry : Definition

A simple triangle has many angles to it. Trigonometry is the study of the relationships between the angles and the lengths of the sides of a triangle. Mostly it helps study triangles with one right angle, that is an angle of 90 degrees.

## Who is the Father of Trigonometry?

Since 3000 BC people have tried to study the stars and the planets and figure out their patterns. Most of you must have looked up at the night sky and wondered about the stars yourself. For ages people wrongly believed that the stars and the planets circle around the earth. The Greek astronomer Hipparchus in 140 B.C, discovered that a system of imaginary right angles connecting the earth with the planets or stars could help in studying the movements of the same. This was the beginning of trigonometry.

## Trigonometry Formulas

Let us teach you a simple way to remember the formulae for a right angle triangle. The side opposite to the right angle is a hypotenuse denoted by the letter ‘h,’ the base is the horizontal line denoted by ‘b’ and the vertical line is called the perpendicular denoted by the letter ‘p.’ The angles are a function of sine, cosine and tangent.

Just remember these lines “some people have, curly black hair, through proper brushing.” If we elaborate, the first letter of every word stands for the functions and their relationships with the sides of the triangle, that is;

S(ome)ine θ = p(eople)erpendicular/h(ave)ypotenuse

C(urly)osine θ= b(lack)ase/ h(air)ypotenuse

T(hrough)an θ= p(roper)erpendicular/ b(rushing)ase

The rest of the functions are Cotangent (opposite of tangent, that is, 1/tan θ), Secant (opposite of cosine, that is, 1/ cosine θ) and Cosecant (opposite of sine, that is, 1/sine θ).

So the next time you are asked to learn formulae for trigonometry, remember that it is one way to reach for the stars.

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Thank you Shubham!

Brilliant learning technique